Energy-efficiency is a serious consideration in building design and construction. Many building codes require builders to minimize energy requirements to maintain comfortable living spaces.
One of the most common energy loss in a building is due to the heat transfer through the attic. In warm climates, heat builds up in the attic from solar energy incident on the roof or from heat transferred up from the living space. If the attic is allowed to become too warm, the installed insulation becomes ineffective and the attic heat is transferred to the living space below.
In colder climates, moisture builds up in the attic, sometimes significantly decreasing the efficiency of the insulation. The moisture, regardless of its numerous potential origins, left unchecked will build up and potentially cause extensive damage within the structure. Moisture originating from the shower, kitchen steam or the like not only potentially decreases the insulating value of insulation, but also potentially leads to mould and mildew growth.
Hence, it is well known in the home building industry that proper circulation of air within the attic zone and above the level at which the insulation is installed is essential to avoid moisture build-up during cold winter months and to maintain the un-insulated attic space at a reasonably low temperature during warm summer months. Early efforts at minimizing energy losses through the attic focused on the insulation between the living space and the attic and ignored the effects of the heat and/or moisture build-up. As insulation improved, a point was reached where more insulation was not necessarily better or possible due to space limitations.
Numerous attempts have been made to alleviate this problem by installing vents at various points in the roofing structure. One common technique is to include vents or venting apertures on the underside of the soffite of the roof as, for example, on the underside of the eaves. While this practice allows some of the heat to escape, the ventilation provided remains poor. Indeed, because the vents are located on the underside of the eaves, the heat must build up to relatively high levels before it is forced downwardly out of the vents due to the fact that heat naturally rises. This also causes non-uniform heat distribution within the attic or roof structure.
Since the heat rises, the temperature closest to the roof will consistently remain at temperatures higher that that of the areas further away from the roof and near the eaves. Also, in sloped roof structures, the heat will concentrate adjacent the apex creating higher temperatures of the apex, which steadily decrease along the roof line toward the eaves. Hence, the air allowed to escape at the eaves is not even the hottest air.
Other attempts have been made to increase ventilation. In one common technique, a venting aperture is cut in various parts of the roof and then covered with a box-like ventilation duct. Static roof ventilators also commonly referred to as “pot vents” typically include three main components. Conventional pot vents typically include a flange or base portion, a conduit or duct portion and a hood or cover portion.
The flange is nailed or otherwise secured to the roof deck over a similarly sized aperture as with the conduit portion. Typically, the leading edge of the flange is positioned over a course of shingles, while additional courses are laid over the flange and cut to fit around the conduit. The hood portion, which is rigidly attached to the flange, prevents moisture penetration in most cases.
Turbine-type roof ventilators are also sometimes used. These turbine roof ventilators typically include a sleeve on the top end of which is mounted a rotatable turbine fluid. Typically, the turbine fluid includes a closed circular, usually convex upper end which prevents ingress of rain into the sleeve and thus into the roof chamber, a lower ring and a series of arcuate turbine blades extending from the lower ring to the upper end through which hot air flows. The turbine blades are rotatable either due to winds or breezes or to the flow of air from out under the roof through the turbine.
Whether of the turbine or static type, most roof ventilators are typically constructed for a given predetermined roof slope or pitch. So-called roof jacks are sometimes provided to connect the outlet of the roof-mounted air handler such as a ventilator to an air duct which emerges from the roof. Prior art roof jacks are typically constructed to couple the typically horizontally oriented aperture at the bottom of the ventilator to the slope or pitch of the roof. Generally each roof jack must be specifically constructed to fit the slope or pitch of the roof upon which it is to be used.
Accordingly, roof jack suppliers are required to maintain a relatively large inventory of roof jacks in order to accommodate the full range of slopes or pitch which are encountered in the building industry. Roof jacks suppliers must also stock roof jacks having different sizes in terms of cross-section in order to meet the needs of various duct and exhaust outlet sizes which are encountered in roof-mounted ventilators.
Consequently, roof jack suppliers are faced with the problem of high costs and high storage space if they want to be able to supply roof jacks accommodating the full range of slopes and cross-sectional diameters encountered in the industry.
Even in cases wherein a given stock roof jack is available and used for a given roof pitch or slope, the slope of the roof may be slightly deviant from the design value and the stock roof jack may not fit the angle perfectly. In such cases, the misfit may cause air leakage from the system or may cause the ventilator to be mounted at a slight angle which could, in turn, cause problems in operation of the ventilator. Accordingly, there exists a need for and adjustable ventilator roof jack.
The prior art has recognized the need for adjustability of roof jacks and, hence, several patents disclose different types of adjustable structures. For example, U.S. Pat. No. 4,526,091 naming Ronald W. Sharp as inventor and issued Jul. 2, 1985 discloses an adjustable roof jack wherein a single sheet metal pattern comprises a portion of the lower and upper section of duct and wherein the duct sections are connected, each to the other, by means of a sheet metal bend hinge in a single sheet metal pattern thereby allowing adjustment of the angle between the upper and lower duct sections.
Also, U.S. Pat. No. 5,409,266 naming George C. Baker as inventor and issued Apr. 25, 1995 discloses an adjustable roof jack including a lower rectangular box-like member which is attached to the roof. An upper rectangular box-like member is made for attachment to a roof-mounted air handler. The front and side of the upper box-like member extend downwardly over the corresponding side and front of the lower roof-mounted member. The upper member is pivotally connected to the lower member at pivot points located through the side, intermediate front and back of the two members. The front of the members faces the center or higher portion of the roof and the edge of the front of the upper member is folded into an S-shaped configuration. The upper edge of the front of the lower member extends into a pocket in the S-shaped configuration to provide a sliding seal between the two parts as the upper member is pivoted relative to the lower member to accommodate the roof pitch.
Although allowing for some degree of angle adjustability, these prior art devices nevertheless suffer from numerous drawbacks. One of these problems is that they are inherently limited by their structural design in terms of range of angular adjustability.
Also, the configuration of some prior art adjustable roof jacks sometimes leads to losses or reductions in terms of effective cross-sectional area through which the air may flow when the roof jack is bent so as to provide for angle adjustability. The configuration of some prior art adjustable roof jacks sometimes unduly restricts the flow of air and/or creates air leaks.
Furthermore, some prior art adjustable roof jacks suffer from being made out of at least two or three independent components that must be assembled together either at the manufacturing site or at the installation site. This not only leads to increased manufacturing, installation or operational costs but also eventually leads to leakage between the assembled components. Accordingly, there exists a need for an improved adjustable ventilator roof jack.
Advantages of the present invention include that the proposed roof jack allows for the connection of a roof-mounted air handler such as a ventilator to an air duct extending through roofs of various slopes or pitch. The proposed roof jack allows for angular adjustability through a set of quick and ergonomic steps without requiring special tooling or manual dexterity. Also, the proposed roof jack allows for angular adjustment thereof prior to being installed on the roof, hence reducing the overall installation time.
Still furthermore, the proposed roof jack allows for angular adjustability with minimal compromise of the cross-sectional effective area through which the air is guided and with minimal flow obstruction and leakage. Yet, still furthermore, the proposed ventilator roof jack is designed so as to reduce the risks of leakage through its sections and so as to be manufacturable through conventional forms of manufacturing using a reduced number of components, hence providing a roof-jack that will be economically feasible, long-lasting and relatively trouble-free in operation.